Finding the Electromagnetic Counterparts of Cosmological Standard Sirens

摘要: The gravitational waves (GWs) emitted during the coalescence of supermassive black holes (SMBHs) in mass range ~104-107 M?/(1 + z) will be detectable out to high redshifts with future Laser Interferometer Space Antenna (LISA). distance and direction these standard sirens can inferred directly from GW signal, a precision that depends on masses, spins, geometry merging system. In given cosmology, LISA-measured luminosity translates into redshift shell. We calculate size shape corresponding three-dimensional error volume which an electromagnetic counterpart LISA event could found, taking account errors background cosmology (as expected by time flies), weak lensing (de)magnification due inhomogeneities along line sight, potential source-peculiar velocities. Weak-lensing largely exceed other sources uncertainties (by factor ~7 for typical at z = 1). Under plausible assumption SMBH-SMBH mergers are accompanied gas accretion leading Eddington-limited quasar activity, we then compute number quasars would found volume, as function BH redshift. Low offer best opportunities identify counterparts cosmological sirens. For ~4 ? (105-107) M? SMBHs, typically contain single near-Eddington ~ 1. If SMBHs spinning rapidly, is smaller may unique 3. This allow straightforward test hypothesis events bright activity and, if proves correct, guarantee identification event, B-band LB (1010-1011) L?. Robust identifications unprecedented tests physics SMBH accretion, such measurements Eddington ratio. They clarify role catalyst coalescences also alternative method constrain parameters.